I finally got around to swapping the hydraulic couplers on my 455. I checked implement pressure, and was reading around 800 psig at full engine RPM.

So, of course I want to shim the relief. lol

My question comes to the 3 point. I've been using it to pull fence posts around the property, and its been doing great even at low pressure. What problems could I run into if I boost hydraulic pressure to 1250 psig or so?

Rear tires are Kenda K502 with a max load of 1780 lbs inflated to 20 psig, so I don't expect any issues there.
--Alex

How do you get a chain to bite enough to lift the post without just sliding up it? I've wanted to use the 3pt on my 2520 for this before but couldn't think of how to 'grab' the post. The picture above is the obvious first guess but I just figured there would be no grabbing power.

The typical 3PH lift cylinder has a 2" bore and a 4" stroke, and a GTs hydraulic system runs at 950 psi max, unless shimmed aftermarket. This gives it a maximum force potential of 2985 lb when extending. Unlike the larger tractors, most 3PH lift cylinders in GTs lift by pulling which will entail the loss of the cross sectional area of the rod for the area that pressure is applied. With a leverage of approximately 4:1 (cylinder stroke to 3PH arm lift distance, even extending will only result in 746 lb of lifting force. Even if the rod is only 3/4" in diameter, that will result in 14% less lifting power when retracting, or 104 lb less, before geometry comes into play. The geometry can further reduce the actual lifting force by 30% or more, or 193 lb. Max lift at the ends of the arms is thus reduced to as low as 449 lb to get maximum stroke for lifting with the 3 PH.

Heavy GT rear axles are rated for a maximum of 500 lb of weight behind the rear axle, usually an implement (tiller, snow blower, or ballast box)) on the 3PH.

A 3PH will not lift the front wheels of a heavy GT off the ground, but any FEL will usually lift the back wheels and the operator of a heavy GT off of the ground, and usually including liquid ballast and wheel weights, at 950 psi.

There is a reason why my GT w/ FEL carried a minimum of 400 lb of ballast. Normal ballast load was 650 lb, and it has carried as much as 865 lb, and still lifted the back wheels off the ground. That's over one ton of lift capability at 1500 psi available for pulling fence posts.

Beats the heck out of 449 lb, and has a 72" stroke besides.

The reason my loader hydraulics has a relief setting of 1500 psi is that it also supports my log splitter.

I've lifted things with the 3 point that the fel wouldn't touch! Like a very heavy chipper.

I assume that you used the Nortrac CUT with its 875 lb 3PH lift capacity, and not the JD 445 GT?

After using my GT loader for 22 years, the loader lifting capability of my SCUT didn't impress me either. It can barely lift the back of that old GT high enough to push into the garage without it's rear wheels! But before I retired the GT, it's loader lifted the back end of the SCUT, including the 800 lb back hoe, clear off the ground. And yes, the back tires of the GT were in the air as well, with it's 650 lb of ballast.

I assume that you used the Nortrac CUT with its 875 lb 3PH lift capacity, and not the JD 445 GT?

After using my GT loader for 22 years, the loader lifting capability of my SCUT didn't impress me either. It can barely lift the back of that old GT high enough to push into the garage without it's rear wheels! But before I retired the GT, it's loader lifted the back end of the SCUT, including the 800 lb back hoe, clear off the ground. And yes, the back tires of the GT were in the air as well, with it's 650 lb of ballast.

You are correct. The Nortrack has the 5' FEL. The 445 has nothing active on the rear.......it's primary use is mowing.

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